Method of producing electric heaters.



W. S. HADAWAY, JR.

METHOD OF PRODUCING ELECTRIC HEATERS.

APPLICATION FILED MAY 14. 1914.

. 'heater 15, an expander 20, and a workin. H

WILLIAM s. nanawar, .m, or new noonnmn, NEW roan amnion orrnonocxne ELECTRIC renames.

icense.

Applicationfild May 14, 191 serial No. 838,442.

. T all whom it may concern:

have invented certain, new and useful Improveinents in Methods of Producing Electric Heaters, of which the followingis a specification, reference being had to the accompanying drawings, forming a part thereof.

My invention relates to electric heaters and particularly to soldering irons and like appliancesi having a cylindrical or prismatic form. I One object of niy'invention is to provide a simple method for advantageouslyproducing a ruggetland compact heater of the character above indicated that shall eilec-v tively transfer the generated heat to the working surface. I I

()ther objects and advantages of my invention will be set forth hereinafter, and in order that myinvention maybe thoroughly understood, 1 will now proceed to describe the same in the following specification, and then point out the novel features thereof in appended claims.

Referring to the drawings: Figure 1 a sectional view illustrating the princi i nal parts, before they are assembled, of a heater embodying my invention. The same parts assembled 1n loose contact are similarly shown in Fig. '2. The next step in carrying out the method of my invention is illustrated in Fig. 3 which also shows the parts in section. The completed body of a sole dering iron or like implement is'shown iii section in Fig. 4:. Fig. 5 'is a detail View of a heating element which is suitable for use in the'device shown in the other figures,

the casing or armor being broken away to disclose the resistance member and its insu- Figs. 1 to 5 inclusive comprises an outer shell 10, an armored and constructed of steel' or other material.

having mechanical strength and rigidity.

Its form and composition Iarehow yer determined to a certain extent by the service H to which it is applied. As a convenient Specification of Letters Patent.

PatentedDee. M 1915.

means for aiiixing a sup orting member or handle 11, it is internal y threaded at one end as shown at 12.

While the heater may have any suitable form and be constructed in any well known manner, it may advantageously comprise a resistance ribbon 16 having lateral'slo'ts 17 cut alternately from opposite edges to form a tortuous path for the electric current, thin insulating strips 18 and a sheet metal armor 19. Mica may suitably be usedigt'or the in sulation and copper for the armor.

The expander 20 is made of relatively soft and highly conductive metal such as copper and is first formed'intoa hollow cylinder having relatively thick walls and a smooth cylindrical bore as shown in Figs. 1, 2 and 3. i y

The'device is assembled and completed as follows: The parts are so constructed that they may be readily assembled in a preliminary way by merely forcing them one within the other into the relation shown in Fig. 2. They are then placed in a recess31 of a die which has a shoulder 32 on which the outer ends of the parts 10, 15, 20 rest. A mandrel 33 is next forced through the expansion member 20 under very high pressure. The mandrel has enlargement 34 which is larger in diameter than the bore of the member 20, and consequently, as it is forced through it, therelatively soft metal of which the me er 20 is. 'composedfis swaged, forced outwardly or extruded and thereby the heater i5 is subjected to high pressure which is -continuously maintained after the mandrel is removed. theshell 10 being sufiiciently hard and rigid to With f stand the Strain put upon it bytl'ie mandrel.

After this part of the process. is complete the cylindrical bore of,'the member 20 is either provided wit screw threads. 2l'as shown in Fig.4, to operate with a screwthreadedsh'ank 26 of the work or body -mem-' ber 25, or is otherwise adapted to cooperate with a projection or some part of the work- 'ing member. For example, the memberQO 'may be provided with a taper bore to receive a taper projection 26 as shown in Fig. 6.- Among be following may be emphasized. The working member is readily removable from the device and may be replaced when worn heating element is subjected is independent theadvantages of my invention 11c 01' damaged. The pressure to which the f gm 7 mee eee of the generatec'l heat to the working ele-.

ment. reason of itsi'nnction the member '20 may be termed swaged or extruded soft metal compression member.

The size and arrangement of parts of the cleviee illustrated may be varied Within the spirit scope of'my' invention and I .inteniithaft only such limitations be imposed as are indicated in the appended claims.

1. Thexniethodof forming an annular electric heater that consists in assembling a' heater element between a relatively rigid reaction member and a relatively soft expension member and swa'ging the soft member to the heater element under permaf nent compression.

2. The methocl of forming a cylindrical electric heater that consists in assembling an annular heater element over a relatively soft tubular expansion member anal Within a relatively rigid reaction member ens extruding the soft tubular member to coinpress the heater element.

3. The method of forming a, cylindrical electric heater that consists in assembling a tubular electric heater element between a soft tubular expansion member within and a rigid sleeve or holder Without, and forcing 'a rigid expanding tool through'the opening in the soft tubular expansion member.

In testimony whereof, I have hereunto set my hand this 12 day of May, 191%, in the presence of two subscribing Witnesses WILLiAM s. HADAWAY, JR.

'Witnesses:

F. GRAVES, ETHEL COHEN. 

